1. Field of the Invention
This invention relates to fluid contacting apparatus for mass transfer and cooling operations and more particularly, to a liquid-air extended surface fluid contact medium which is defined by specially designed fluid contact plates having multiple vertical and horizontally oriented fins interconnected by diagonal fins and provided with extending pins and pin slots as well as T-connectors and T-slots, for connecting individual plates together in front-to-back and stacked relationship. The fluid contact plates are designed to distribute a falling stream of water or other liquid into a thin film in order to provide an extended liquid surface for air or alternative fluid contact with the liquid in cooling or mass transfer operations. The fluid contact is used in such applications as cooling towers, absorption towers, stripping units, cooling units for poultry houses and greenhouses and other equipment for interfacing gases and liquids and in a preferred embodiment, for the evaporative cooling of air by contact with water. The fluid contact plate of this invention is characterized by an inert material of construction, a high void volume which effects a low resistance to the flow of water or other cooling fluid, a large surface area per unit of volume and a low density, in order to provide an extensive contact matrix surface with minimum weight.
The fluid contact plate of this invention is particularly well suited for use in cooling poultry houses and greenhouses where a primary problem associated with growing large numbers of chickens, turkeys and other poultry, as well as flowers and vegetables such as tomatoes, is that of maintaining a suitably cool temperature in the protective structures during hot weather. Poultry such as chickens and turkeys are sensitive to heat and large poultry losses have been experienced in commercial poultry houses in hot summer weather. Furthermore, the blooms on certain vegetables such as tomatoes will not "set" at temperature above about 80.degree. F. Greenhouses and poultry houses are typically cooled by large exhaust fans located in one end of the structure for circulating air through screened openings at the opposite end and cooling the interior of the structure to a desired temperature level. However, in the heat of the summer, these fans will only reduce the temperature in the structure to a level which is determined by the air temperature outside the structure and additional cooling is frequently necessary to reduce the temperature in the structure to an acceptable level. This additional cooling is normally provided by installing cooling panels across the screened openings in one end of the structure, which panels are designed with wafer-like contact elements that are saturated with water in order to provide an evaporative contact surface to cool the air circulated through the panels by the exhaust fans. In a typical installation these panels are fabricated of paper and are corrugated and wafered in order to present maximum contact surface area to the air current for evaporative cooling purposes. The panels are manufactured in selected sizes and are typically placed in a supporting rack to facilitate wetting the panels by a discharge of water through a distribution header located above the panels and attached to the rack. The water which remains after evaporative cooling is then collected to a trough sump or drain system and is returned to a sump pump or is pumped directly from the receiving trough or pipe back through the distribution header.
2. Description of the Prior Art
Various apparatus are known in the art for providing gas-liquid contact for the purpose of cooling a gas, such as in cooling towers and in other unit operations where it is necessary or desirable to expose a large liquid area in a small volume or in a short distance. Of the prior art devices designed to effect such liquid-gas contact, among the most efficient are the corrugated contact structures which are constructed of a plastic or paper material, which structures achieve a desirable weight reduction and satisfy necessary high void volume and large surface area requirements. However, problems have been experienced with many of these prior art devices, in that the falling liquid tends to "channel" or flow in streams across the textured contact surfaces, rather than completely wet the surfaces. This condition creates dry areas in the structure and reduces the overall contact efficiency.
Typical of the prior art fluid-contact devices is the structure disclosed in U.S. Pat. No. 2,793,017 to Douglas E. Lake, entitled "Apparatus For Distributing Falling Liquid in Thin Films". The Lake invention as embodied in this patent includes an assembly of corrugated sheet elements arranged in stacked relationship to provide an extended fluid contact surface for use in such devices as trickle filters, cooling towers, absorption towers and the like. The corrugated sheet elements are manufactured from organic thermoplastic sheet materials, including a polymer or copolymer of styrene. A similar gas-liquid contacting device is disclosed in U.S. Pat. No. 3,485,485 to Heinz Faigle, which "Cooling Screen" is characterized by a plurality of sheets having a median longitudinal axis with corrugations extending in the longitudinal direction on either side of this axis and offset from one another on either side of the longitudinal axis. When the structure is viewed transversely, the ridge of one of the corrugations is aligned with a valley of another corrugation, the ridges and valleys of the corrugations being equal. When the structure is viewed longitudinally, unimpeded passageways are formed between the adjacent sheets. U.S. Pat. No. 3,792,841, to Karl G. Munters, discloses a "Contact Apparatus For Liquid and Gas", which includes a contact body having first and second sets of corrugated sheets arranged with the sheets of the first set disposed alternately with the sheets of the second set. The sheet corrugations provide channels or passageways which penetrate the contact body from edge to edge, with both the horizontal and vertical components thereof defining a fluted configuration. Another fluid contact device is disclosed in U.S. Pat. No. 3,704,869, to Ronald Priestley and includes packing sheets characterized by spaced, parallel units, each of which units defines a sector of a hollow, corrugated tube connected by planer portions of the sheets, the assembled sheets providing a regular array of hollow corrugated tubes. U.S. Pat. No. 2,977,103 to L. R. Smith et, al., discloses a "Cooling Tower Structure", which includes a rectangular, box-like container that is open at the top, the sides and bottom of which container are formed of U-shaped wire members positioned by cooperating longitudinal wires. Solid metal sheets define the ends of the container and cooling plates or baffles are placed in the frame in parallel, spaced relationship to achieve the desired fluid contact. U.S. Pat. No. 4,031,180, entitled "Cooling Pad System", discloses a cooling system which uses wafered panels to create an evaporate cooling surface for cooling a building. U.S. Pat. No. 4,389,352, entitled "Cooling Pad Support System", teaches a support apparatus for mounting a cooling system such as the system disclosed in U.S. Pat. No. 4,031,180, on the wall of a building. Other patents which disclose liquid contact apparatus of various design for creating mass transfer and evaporative cooling surfaces are as follows: U.S. Pat. No. 1,142,809, to J. F. Grace, entitled "Cooling Tower"; U.S. Pat. No. 2,665,123, to D. D. Foster, et al. entitled "Apparatus For Treating Gases With Liquids"; U.S. Pat. No. 2,961,226, to A. B. Goettle, entitled "Evaporative Cooler and Water Control Means Therefor"; U.S. Pat. No. 3,208,204, to Per-Oskar Persson, entitled "Eliminator For Separation of Liquid From Gas"; U.S. Pat. No. 3,965,691, to Van Huis, entitled "Cooling System For Poultry Houses"; U.S. Pat. No. 4,312,819, to Billy M. Leyland, entitled "Air Cooling Apparatus", and U.S. Pat. No. 4,477,394, to Charles M. Armstrong and Eddie D. Duke entitled "Fluid Contact Panel."
One of the problems realized in prior art cooling systems and particularly in systems utilizing evaporation cooling in cooperation with one or more exhaust fans, is that of providing a desired degree of cooling inside the structure as the temperature outside the structure rises. For example, on spring or fall days when the outside temperature is not extremely high, less cooling is necessary in the structure than under circumstances where the temperature is very high, such as during mid-summer. Furthermore, introduction of distributing of water into the cooling pads or panels in such a manner as to completely saturate the panels instead of causing the water to "channel" through the panels and leave dry areas in the panels, is difficult.
Another problem associated with many of the prior art liquid-gas interface structures is the relatively great weight of such devices and particularly those structures which are constructed of metal and wood. Another problem is the lack of sufficient contact surface and voids, a condition which frequently results in excessive pressure drop across the cooling matrix itself. Still another problem which is particularly apparent in poultry houses, where water should not be introduced into the house by means of the cooling system, is that of entrained water which is introduced into the house with the air which circulates through the cooling system. Since poultry and particularly chickens, are highly susceptible to disease when wet, the introduction of such entrained water with the air is highly undesirable.
Accordingly, it is an object of this invention to provide a new and improved medium for effecting efficient cooling contact between air and water, which medium is characterized by a high percentage of voids, minimum pressure drop in the air phase, reduction of channeling of the downward flowing water and a large surface area for effecting good interface contact between the air and water.
Another object of the invention is to provide a new and improved, extended surface contact apparatus having multiple vertically, horizontally, and diagonally oriented fins arranged in a repeating array or matrix for use in cooling air by using a downward flow of water through the apparatus, with air circulated through the matrix transversely to the water flow, which apparatus is characterized by good resistance to corrosion, lightness of weight and a high percentage of voids to wettable contact surface area, the surface area further designed and oriented in a matrix to minimize channeling of the liquid and maximize deposition of a film of water on the contact surfaces to maximize air-water contact efficiency.
Yet another object of this invention is to provide new and improved fluid contact plates which are substantially inert and are capable of assembly into an interlocking extended surface matrix for interface contact between water and air, which plate are each characterized by multiple vertically, horizontally and diagonally oriented fins arranged in a matrix array and provided with projecting pins and internal pin slots, with accompanying T-connectors and T-slots for connecting the plates in front-to-back and stacked relationship, which plates are light in weight, resistance to corrosion and can be utilized in many air cooling and mass transfer applications.
Another object of this invention is to provide a new and improved cooling fluid contact plate apparatus for use in structures such as greenhouses and poultry houses, which apparatus is designed to facilitate efficient air-water contact by presenting an extended surface cooling film matrix characterized by multiple fins and utilizing one or more screens which are designed to minimize the introduction of water into the structure as liquid droplets entrained in the air stream.
Another object of the invention is to provide a new and improved fluid contact plate cooling apparatus for use in cooperation with exhaust fans to cool such structures as greenhouses, poultry houses and the like, which apparatus is characterized by multiple fluid contact plates joined in front-to-back relationship by means of pins and cooperating pin slots and vertically attached to T-connectors and corresponding T-slots, to provide a cooling surface of desired thickness and height. Each of the plates includes multiple vertically, horizontally and diagonally positioned fins organized in a repeating matrix, with a screen or screens of selected mesh size located in the matrix structure, in order to provide maximum efficiency in contacting air with water flowing through the matrix structure, to cool the air and the poultry house, greenhouse or other structure.